This application claims the priority of Korean Patent Application No. 2004-11322, filed on Feb. 20, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a camera module package having an image sensor module on a circuit board, and, more particularly, to an image sensor module on which a circuit board and a semiconductor device mounted on the circuit board are connected by a wire bonding method, the image sensor module being included in a camera module for small electrical appliances by which moving picture can be transmitted and pictures can be taken, such as a mobile phone, a notebook computer, a personal digital assistant (PDA), a camera for a monitor, a rear view camera that is installed on a car bumper, and a door/interphone.
2. Description of the Related Art
FIG. 1 is a schematic cross-sectional view showing the structure of a camera module package that incorporates an image sensor module using a wire bonding method.
Referring to FIG. 1, the image sensor module 10 is formed by mounting an image sensing device unit 12 on a printed circuit board 11 that contains a circuit pattern. A housing 20 is attached to the printed circuit board 11 to form a camera module package incorporating the image sensor module 10, which includes the printed circuit board 11 and the image sensing device unit 12. The housing 20 protects the camera module, including the image sensor module, from the external environment and maintains an airtight state within the housing.
The housing 20 includes a lens barrel unit 21, a protective cover 22, and an infrared ray and reflection prevention filter 23. The protective cover is installed on the outer end portion of the lens barrel unit 21, through which passes images to be photographed. The infrared ray and reflection prevention filter 23 is installed on the inner end portion of the lens barrel unit 21, that is, on the upper portion of the image sensing device unit 12.
The protective cover 22 is for protecting the image sensor module 10 from the external environment and maintaining airtight status. Also, the infrared ray and reflection prevention filter 23 is for shielding infrared rays induced into the bonding camera module package 20 and preventing light from being reflected. An infrared ray (IR)-cut coating is formed on the upper surface of the filter 23, and an anti-reflection coating is formed on the lower surface of the filter 23. A lens 24 for taking photographs is installed in the lens barrel unit 21, and a thread for moving the lens in order to focus is formed on an inner surface of the lens barrel unit 21.
Here, the image sensing device unit 12 includes an image sensing device 12a and a pixel area part 12b. The pixel area part 12b is formed on a range of the image sensing device 12a, on which a bottom surface of the lens barrel unit 21 is located. The image is formed by passing through a space formed in the pixel area part and in the lens barrel unit 21.
A board connecting pad 14 and a device connecting pad 15 are formed on the printed circuit board 11 and the image sensing device unit 12, respectively, in order to electrically connect them to external devices. In order to electrically connect the printed circuit board 11 and the image sensing device unit 12, the board connecting pad 14 and the device connecting pad 15 are connected to each other by a bonding wire 16.
Here, the board connecting pad 14 is formed on an outer portion on the printed circuit board 11 where the image sensing device unit 12 is not located. The device connecting pad 15 is formed on an outer portion of the image sensing device 12a where the pixel area part 12b is not located. The device connecting pad 15 is electrically connected to the board-side connecting pad 14 through the wire bonding 16.
As described above, in a case where a small size camera module for transmitting moving pictures and for taking pictures is constructed using the conventional packaging method, which electrically connects the printed circuit board and the semiconductor device through the wire bonding method, a predetermined distance should be ensured to exist between the connecting pad of the semiconductor pad and the connecting pad formed on the circuit board. Thus, there is a limit for reduction of the width of the semiconductor package.
A predetermined effective distance should be maintained between the lens 24 and the pixel area part 12b in order to focus the image on the pixel area part. According to the camera module package including the image sensor module by the wire bonding of the conventional art, since the image sensing device is mounted on the circuit board and the pixel area part is formed on the upper surface of the image sensing device, there is a limit to reducing the height of the image sensor module for ensuring the effective distance.
Generally, in order to construct a chip scale package (CSP) that overcomes the limits of the package size, the circuit board and the semiconductor device thereon may be electrically connected in a flip chip bonding method. However, in order to use the flip chip bonding method, new equipment for performing the flip chip bonding process needs to be furnished. In addition, if the semiconductor package uses the flip chip bonding method, although the width of the image sensor module can be reduced, there is a limit to reducing the height of the image sensor module.